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A comment on US companies are producing heat pumps that work below -20F(-28C). Parent comment

Re:US companies are producing heat pumps that work below -20... by newZWhoDis on Wednesday December 28, 2022 @11:41AM (#34162761)
Well that installer cutoff was likely waaaaay too high. Your heat pump should be fine to 30F, maybe even 25F before needing gas.

Modern systems are 24 SEER and good to -5, and these research units take that to the next level.

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Re:US companies are producing heat pumps that work below -20... by Majromax on Wednesday December 28, 2022 @01:29PM (#34164061)
> Well that installer cutoff was likely waaaaay too high. Your heat pump should be fine to 30F, maybe even 25F before needing gas

One possibility might be that the unit lacks de-icing circuitry. If that were cut for cost optimization, the unit would still work fine for cooling and for moderate-temperature heating, but anywhere near 30F it would ice up and stop working.

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Re:US companies are producing heat pumps that work below -20... by bowow on Wednesday December 28, 2022 @02:04PM (#34164497)
Unfortunately only the very top-of-the-line (very expensive) variable speed compressor units are rated for anything close to 24 SEER / -5F (unless that's what you meant by modern systems).
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Re:US companies are producing heat pumps that work below -20... by rudedogg on Wednesday December 28, 2022 @03:50PM (#34165787)
> Well that installer cutoff was likely waaaaay too high. Your heat pump should be fine to 30F, maybe even 25F before needing gas.

The parent post was saying it's cheaper to use natural gas at those temps, so that's why the installer did the cutoff there.

You can look at COP numbers for heat pumps here: https://ashp.neep.org/#!/product_list/

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